Until servo systems became more reliable, more powerful, and less expensive, they simply were not as good a choice, and they were seldom cost effective. Some machines did use a lot of shafts, gears, and chain drives, but that was often because there was no other way available to keep a bunch of motions in the proper relationship. HYdraulics were often used because there was no other economical way to provide that much foce in that small a volume.
So really, don't fault the older mechanisms, since there was not much choice.
The modern servo controllers are providing control options that did not exist before, and at power levels that were simply not available. So we do see that the new generation of servo systems does offer a way to do things thatwas not available previously. The older technologies were not a poor choice, they were the only choice.
But the new networked servo systems, while providing a lot of benefits are also bringing along a few challenges. Systems that previously were locked into the correct sequence of motions are now able to be accidently programmed to crash and destroy themselves, and in a hurry, as well. So now the motion programmer must pay far greater attention to a lot more details, and the same goes for any who would attempt to make small changes to the programs. So there are some very real and quite serious concerns when changing from mechanical systems to interlinked servo systems.
Nice round-up of the technologies that are modernizing factories, making them safer, more efficient and generally more productive. I would add robotics to the list as well, especially with efforts like Rethink Robots' Baxter (http://www.designnews.com/author.asp?section_id=1386&doc_id=263186) and more autonomous and safer robotics coming into play. Perhaps it's a little early for mass adoption but I think it will eventually trend in that direction.